1 /* SPDX-License-Identifier: GPL-2.0-only */
4 * Copyright (C) 2011 Novell Inc.
7 #include <linux/kernel.h>
8 #include <linux/uuid.h>
10 #include "ovl_entry.h"
13 #define pr_fmt(fmt) "overlayfs: " fmt
16 __OVL_PATH_UPPER = (1 << 0),
17 __OVL_PATH_MERGE = (1 << 1),
18 __OVL_PATH_ORIGIN = (1 << 2),
21 #define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER)
22 #define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE)
23 #define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN)
25 #define OVL_XATTR_NAMESPACE "overlay."
26 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
27 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
40 /* Pure upper dir that may contain non pure upper entries */
42 /* Non-merge dir that may contain whiteout entries */
46 /* Inode number will remain constant over copy up. */
63 * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
65 * origin.fh - exported file handle of the lower file
66 * origin.uuid - uuid of the lower filesystem
68 #define OVL_FH_VERSION 0
69 #define OVL_FH_MAGIC 0xfb
71 /* CPU byte order required for fid decoding: */
72 #define OVL_FH_FLAG_BIG_ENDIAN (1 << 0)
73 #define OVL_FH_FLAG_ANY_ENDIAN (1 << 1)
74 /* Is the real inode encoded in fid an upper inode? */
75 #define OVL_FH_FLAG_PATH_UPPER (1 << 2)
77 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
78 OVL_FH_FLAG_PATH_UPPER)
80 #if defined(__LITTLE_ENDIAN)
81 #define OVL_FH_FLAG_CPU_ENDIAN 0
82 #elif defined(__BIG_ENDIAN)
83 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
85 #error Endianness not defined
88 /* The type used to be returned by overlay exportfs for misaligned fid */
89 #define OVL_FILEID_V0 0xfb
90 /* The type returned by overlay exportfs for 32bit aligned fid */
91 #define OVL_FILEID_V1 0xf8
93 /* On-disk format for "origin" file handle */
97 u8 len; /* size of this header + size of fid */
98 u8 flags; /* OVL_FH_FLAG_* */
99 u8 type; /* fid_type of fid */
100 uuid_t uuid; /* uuid of filesystem */
101 u32 fid[]; /* file identifier should be 32bit aligned in-memory */
104 /* In-memory and on-wire format for overlay file handle */
106 u8 padding[3]; /* make sure fb.fid is 32bit aligned */
113 #define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
114 #define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
115 #define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
116 offsetof(struct ovl_fb, fid))
118 extern const char *const ovl_xattr_table[][2];
119 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
121 return ovl_xattr_table[ox][ofs->config.userxattr];
124 static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
126 int err = vfs_rmdir(dir, dentry);
128 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
132 static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
134 int err = vfs_unlink(dir, dentry, NULL);
136 pr_debug("unlink(%pd2) = %i\n", dentry, err);
140 static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
141 struct dentry *new_dentry)
143 int err = vfs_link(old_dentry, dir, new_dentry, NULL);
145 pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
149 static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
152 int err = vfs_create(dir, dentry, mode, true);
154 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
158 static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
161 int err = vfs_mkdir(dir, dentry, mode);
162 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
166 static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
167 umode_t mode, dev_t dev)
169 int err = vfs_mknod(dir, dentry, mode, dev);
171 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
175 static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
178 int err = vfs_symlink(dir, dentry, oldname);
180 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
184 static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry,
185 enum ovl_xattr ox, void *value,
188 const char *name = ovl_xattr(ofs, ox);
189 return vfs_getxattr(&init_user_ns, dentry, name, value, size);
192 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
193 enum ovl_xattr ox, const void *value,
196 const char *name = ovl_xattr(ofs, ox);
197 int err = vfs_setxattr(&init_user_ns, dentry, name, value, size, 0);
198 pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
199 dentry, name, min((int)size, 48), value, size, err);
203 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
206 const char *name = ovl_xattr(ofs, ox);
207 int err = vfs_removexattr(&init_user_ns, dentry, name);
208 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
212 static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
213 struct inode *newdir, struct dentry *newdentry,
217 struct renamedata rd = {
219 .old_dentry = olddentry,
221 .new_dentry = newdentry,
225 pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
226 err = vfs_rename(&rd);
228 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
229 olddentry, newdentry, err);
234 static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
236 int err = vfs_whiteout(dir, dentry);
237 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
241 static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode)
243 struct dentry *ret = vfs_tmpfile(dentry, mode, 0);
244 int err = PTR_ERR_OR_ZERO(ret);
246 pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
250 static inline bool ovl_open_flags_need_copy_up(int flags)
255 return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
259 int ovl_want_write(struct dentry *dentry);
260 void ovl_drop_write(struct dentry *dentry);
261 struct dentry *ovl_workdir(struct dentry *dentry);
262 const struct cred *ovl_override_creds(struct super_block *sb);
263 int ovl_can_decode_fh(struct super_block *sb);
264 struct dentry *ovl_indexdir(struct super_block *sb);
265 bool ovl_index_all(struct super_block *sb);
266 bool ovl_verify_lower(struct super_block *sb);
267 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
268 bool ovl_dentry_remote(struct dentry *dentry);
269 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
271 bool ovl_dentry_weird(struct dentry *dentry);
272 enum ovl_path_type ovl_path_type(struct dentry *dentry);
273 void ovl_path_upper(struct dentry *dentry, struct path *path);
274 void ovl_path_lower(struct dentry *dentry, struct path *path);
275 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
276 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
277 struct dentry *ovl_dentry_upper(struct dentry *dentry);
278 struct dentry *ovl_dentry_lower(struct dentry *dentry);
279 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
280 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
281 struct dentry *ovl_dentry_real(struct dentry *dentry);
282 struct dentry *ovl_i_dentry_upper(struct inode *inode);
283 struct inode *ovl_inode_upper(struct inode *inode);
284 struct inode *ovl_inode_lower(struct inode *inode);
285 struct inode *ovl_inode_lowerdata(struct inode *inode);
286 struct inode *ovl_inode_real(struct inode *inode);
287 struct inode *ovl_inode_realdata(struct inode *inode);
288 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
289 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
290 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
291 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
292 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
293 bool ovl_dentry_is_opaque(struct dentry *dentry);
294 bool ovl_dentry_is_whiteout(struct dentry *dentry);
295 void ovl_dentry_set_opaque(struct dentry *dentry);
296 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
297 void ovl_dentry_set_upper_alias(struct dentry *dentry);
298 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
299 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
300 bool ovl_has_upperdata(struct inode *inode);
301 void ovl_set_upperdata(struct inode *inode);
302 bool ovl_redirect_dir(struct super_block *sb);
303 const char *ovl_dentry_get_redirect(struct dentry *dentry);
304 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
305 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
306 void ovl_dir_modified(struct dentry *dentry, bool impurity);
307 u64 ovl_dentry_version_get(struct dentry *dentry);
308 bool ovl_is_whiteout(struct dentry *dentry);
309 struct file *ovl_path_open(struct path *path, int flags);
310 int ovl_copy_up_start(struct dentry *dentry, int flags);
311 void ovl_copy_up_end(struct dentry *dentry);
312 bool ovl_already_copied_up(struct dentry *dentry, int flags);
313 bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry);
314 bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry,
316 int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry,
317 enum ovl_xattr ox, const void *value, size_t size,
319 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
320 void ovl_set_flag(unsigned long flag, struct inode *inode);
321 void ovl_clear_flag(unsigned long flag, struct inode *inode);
322 bool ovl_test_flag(unsigned long flag, struct inode *inode);
323 bool ovl_inuse_trylock(struct dentry *dentry);
324 void ovl_inuse_unlock(struct dentry *dentry);
325 bool ovl_is_inuse(struct dentry *dentry);
326 bool ovl_need_index(struct dentry *dentry);
327 int ovl_nlink_start(struct dentry *dentry);
328 void ovl_nlink_end(struct dentry *dentry);
329 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
330 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry);
331 bool ovl_is_metacopy_dentry(struct dentry *dentry);
332 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry,
335 static inline bool ovl_is_impuredir(struct super_block *sb,
336 struct dentry *dentry)
338 return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE);
342 * With xino=auto, we do best effort to keep all inodes on same st_dev and
343 * d_ino consistent with st_ino.
344 * With xino=on, we do the same effort but we warn if we failed.
346 static inline bool ovl_xino_warn(struct super_block *sb)
348 return OVL_FS(sb)->config.xino == OVL_XINO_ON;
351 /* All layers on same fs? */
352 static inline bool ovl_same_fs(struct super_block *sb)
354 return OVL_FS(sb)->xino_mode == 0;
357 /* All overlay inodes have same st_dev? */
358 static inline bool ovl_same_dev(struct super_block *sb)
360 return OVL_FS(sb)->xino_mode >= 0;
363 static inline unsigned int ovl_xino_bits(struct super_block *sb)
365 return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0;
368 static inline void ovl_inode_lock(struct inode *inode)
370 mutex_lock(&OVL_I(inode)->lock);
373 static inline int ovl_inode_lock_interruptible(struct inode *inode)
375 return mutex_lock_interruptible(&OVL_I(inode)->lock);
378 static inline void ovl_inode_unlock(struct inode *inode)
380 mutex_unlock(&OVL_I(inode)->lock);
385 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
387 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
389 if (fh_len < sizeof(struct ovl_fh))
392 return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
395 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
396 struct vfsmount *mnt, bool connected);
397 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
398 struct dentry *upperdentry, struct ovl_path **stackp);
399 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
400 enum ovl_xattr ox, struct dentry *real, bool is_upper,
402 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index);
403 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
404 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
406 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
407 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
408 struct dentry *origin, bool verify);
409 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
410 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
412 bool ovl_lower_positive(struct dentry *dentry);
414 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
415 struct dentry *origin, bool set)
417 return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
421 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
422 struct dentry *upper, bool set)
424 return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
428 extern const struct file_operations ovl_dir_operations;
429 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
430 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
431 void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
432 void ovl_cache_free(struct list_head *list);
433 void ovl_dir_cache_free(struct inode *inode);
434 int ovl_check_d_type_supported(struct path *realpath);
435 int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
436 struct dentry *dentry, int level);
437 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
440 int ovl_set_nlink_upper(struct dentry *dentry);
441 int ovl_set_nlink_lower(struct dentry *dentry);
442 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
443 struct dentry *upperdentry,
444 unsigned int fallback);
445 int ovl_setattr(struct dentry *dentry, struct iattr *attr);
446 int ovl_getattr(const struct path *path, struct kstat *stat,
447 u32 request_mask, unsigned int flags);
448 int ovl_permission(struct inode *inode, int mask);
449 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
450 const void *value, size_t size, int flags);
451 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
452 void *value, size_t size);
453 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
454 struct posix_acl *ovl_get_acl(struct inode *inode, int type);
455 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
456 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
458 struct ovl_inode_params {
459 struct inode *newinode;
460 struct dentry *upperdentry;
461 struct ovl_path *lowerpath;
463 unsigned int numlower;
465 struct dentry *lowerdata;
467 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
468 unsigned long ino, int fsid);
469 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
470 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
472 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
473 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
474 struct inode *ovl_get_inode(struct super_block *sb,
475 struct ovl_inode_params *oip);
476 static inline void ovl_copyattr(struct inode *from, struct inode *to)
478 to->i_uid = from->i_uid;
479 to->i_gid = from->i_gid;
480 to->i_mode = from->i_mode;
481 to->i_atime = from->i_atime;
482 to->i_mtime = from->i_mtime;
483 to->i_ctime = from->i_ctime;
484 i_size_write(to, i_size_read(from));
487 static inline void ovl_copyflags(struct inode *from, struct inode *to)
489 unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME;
491 inode_set_flags(to, from->i_flags & mask, mask);
495 extern const struct inode_operations ovl_dir_inode_operations;
496 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
497 struct dentry *dentry);
502 struct dentry *hardlink;
505 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
507 struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry,
508 struct ovl_cattr *attr);
509 int ovl_cleanup(struct inode *dir, struct dentry *dentry);
510 struct dentry *ovl_lookup_temp(struct dentry *workdir);
511 struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr);
514 extern const struct file_operations ovl_file_operations;
515 int __init ovl_aio_request_cache_init(void);
516 void ovl_aio_request_cache_destroy(void);
517 long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
518 long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
521 int ovl_copy_up(struct dentry *dentry);
522 int ovl_copy_up_with_data(struct dentry *dentry);
523 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
524 int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
526 int ovl_set_attr(struct dentry *upper, struct kstat *stat);
527 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
529 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *dentry,
530 struct dentry *lower, struct dentry *upper);
533 extern const struct export_operations ovl_export_operations;